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2023 Volume 0 Issue 9  Published: 2023-09-15
    Special Topic on Autonomous Driving Technology at Chongqing Jiaotong University
  • Rui Li , Xin Wang , Weipeng Yang , Tao Qu , Shuai He
    doi: 10.20104/j.cnki.1674-6546.20230308

    This paper provides a comprehensive review of the application of computer vision technology in the automatic detection of road potholes and objective assessment of road conditions. Typically, cameras and various types of depth sensors are used to acquire two-dimensional and three-dimensional road data for road imaging. Pothole detection is carried out based on computer vision technology, with the main detection algorithms including classic two-dimensional image processing, three-dimensional point cloud modeling and segmentation, deep learning, and their hybrid methods. The hybrid methods, which exploit the advantages of various algorithms, can greatly improve the accuracy of detection. However, while existing algorithms have achieved good results in pothole detection, they still face many challenges, such as the need to improve the robustness of road geometry reconstruction, high algorithm complexity, and the model’s strong dependence on large-scale well-annotated datasets. Therefore, future research should focus more on unsupervised stereo matching algorithms and deep learning algorithms with few samples.

  • Special Topic on Autonomous Driving Technology at Chongqing Jiaotong University
  • Dong He , Maojie Zhao , Zinan Wang
    doi: 10.20104/j.cnki.1674-6546.20230315

    In the context of high-speed mixed traffic and intricate multi-vehicle interaction, existing driving intention recognition models for research vehicles mostly neglect driving styles and vehicle-vehicle information interaction, this paper introduced a novel driving intention recognition model based on an enhanced Bidirectional Long Short-Term Memory (Bi LSTM) network, with the driving trajectory sequence of the target vehicle, driving style, and interaction features of surrounding vehicles as inputs for effective training and learning, to facilitate the classification and recognition of the driving intention feature dataset, specifically considering diverse driving styles. Additionally, the Whale Optimization Algorithm (WOA) was employed to optimize hyperparameters, encompassing the number of hidden layer nodes and learning rate, effectively mitigating the adverse impacts of manual parameter adjustment. The model’s efficacy was validated using the NGSIM dataset, exhibiting an impressive recognition accuracy of 97.5% in precisely identifying vehicle driving intentions.

  • Special Topic on Autonomous Driving Technology at Chongqing Jiaotong University
  • Zinan Wang , Dong He , Maojie Zhao
    doi: 10.20104/j.cnki.1674-6546.20230342

    For the problem of intelligent vehicles recognizing lane line deviation in different environments, this paper proposed a lane line detection and lane deviation warning algorithm based on sliding window search. Firstly, real-time road images were preprocessed, including camera calibration, color and gradient filtering, perspective transformation, etc., and then the sliding window search algorithm was used to detect the lane lines and fit the lane lines using quadratic polynomials. Then, the camera monocular ranging principle was used to calculate the relative position of the vehicle to the centerline of the lane and determine whether it deviated from the lane. The experimental results show that the algorithm’s lane line detection accuracy reaches 98.59%, the lane deviation warning rate reaches 99.58%, and the processed video frame rate is about 25 frames/s, which meets the accuracy and real-time requirements.

  • Special Topic on Autonomous Driving Technology at Chongqing Jiaotong University
  • Weirui Xu
    doi: 10.20104/j.cnki.1674-6546.20230297

    In order to ensure the accuracy of trajectory tracking and maneuvering stability of intelligent vehicles at high speeds on roads with different coefficients of adhesion, the Adaptive Model Predictive Control (AMPC) method was used to estimate the tire cornering stiffness on-line and update the parameters of the vehicle dynamics model in real time under high-speed driving conditions, and the Non-Fixed Step (NFS) discrete method was used to prolong the prediction time domain while the slip stability constraints were added into the objective function, thus maintaining high stability and control in real time under high-speed driving conditions. The proposed method can improve the maneuvering stability and control accuracy when the vehicle is driving on the road with different adhesion coefficients under high-speed driving conditions, as shown in the joint simulation results of CarSim and MATLAB/Simulink.

  • Xiaoliang Luo , Ce Wang , Yangrui Zhang
    doi: 10.20104/j.cnki.1674-6546.20230304

    Hub motor air gap eccentricity leads to electromagnetic force imbalance and torque fluctuation increase affecting the vehicle driving stability. To solve this problem, firstly, the Fourier function was used to derive the relationship curves of inductance, magnetic chain, radial electromagnetic force and torque of the switched reluctance motor concerning the current and angle, and then, the spatial electromagnetic characteristics of the electromagnetic force and torque were analyzed based on Maxwell’s stress tensor method in the two operating conditions. The results show that the air gap eccentricity leads to the imbalance of electromagnetic force and torque at the eccentric position. Then, the contribution weights of structural parameters were determined by sensitivity analysis, and a multi-objective optimization scheme was formulated, finally, the multi-objective optimization search of structural parameters was carried out with the help of NSGA-Ⅱ, and two groups of optimization schemes were screened, of which the optimal scheme C1 improves the optimization results greatly, and the longitudinal and transverse stability of the wheel-hub motor-driven automobile is improved efficiently.

  • Xiaofeng Cao , Hongda Liu , Lin Chen , Chengcheng Yu , Fang Kuang
    doi: 10.20104/j.cnki.1674-6546.20220132

    A test method and test bench for knee module impacting dashboard were proposed and designed, to reproduce the contact of the dummy leg with dashboard in real vehicle crash. The collision process between the knee and the dashboard in the car was studied pertinently, and the knee invasion curve on the dashboard was obtained by the high-speed camera dynamic displacement calculation method, which was interpolated and integrated to obtain the relationship between the injury index of the dummy leg and the amount of knee intrusion on the dashboard, to directly reflect and verify the collision protection performance of the dashboard to the leg.

  • Jiandong Li , Xiangdong Shi , Lei Zhen , Han Liu , Zhiwen Liu
    doi: 10.20104/j.cnki.1674-6546.20230064

    In order to effectively control vehicle NOx emission, this paper studied vehicle NOx emission from the perspective of intake temperature and road conditions with the single factor variable method and obtained the influence rule of different factors on vehicle NOx emission. The results show that with the intake temperature increasing by 10 ℃, the original NOx emission concentration increases by about 5% and the tail gas emission concentration increases by 19%~44%. The influence range of different road conditions on NOx emission shows great difference.